1. Field of the Invention
The present invention relates to a quench tank which cools liquid metal such as liquid metal as a target to which a proton beam is irradiated in a neutron generator and a liquid metal loop which includes the quench tank.
2. Description of the Related Art
Hitherto, a liquid metal loop disclosed in Japanese Laid-open Patent Publication No. 2001-33600 is known. FIG. 18 is a configuration diagram illustrating a liquid metal loop of the related art. A liquid metal loop 900 includes a target 901 which obtains a neutron by irradiating a proton beam thereto, a quench tank 902 which is disposed at the downstream side of the target 901, a circulating pump 903 which is connected to the quench tank 902, a jet pump 904 which is disposed between the quench tank 902 and the circulating pump 903, and a heat exchanger 905 which is disposed at the downstream side of the circulating pump 903. The target 901 forms a liquid metal membrane flow on a back plate 906 by pressing the liquid metal on the curved back plate 906 through a centrifugal force.
The liquid metal is ejected onto the back plate 906 by the function of the circulating pump 903 so as to form a liquid membrane thereon. The liquid metal which passes through the back plate 906 is returned to the quench tank 902 so as to be stored and cooled therein and is sent to the circulating pump 903 by the jet pump 904. Accordingly, the cavitation is prevented due to the increasing back pressure in the suction port of the circulating pump 903. Then, the liquid metal is supplied onto the back plate 906 again by the circulating pump 903. The proton beam is irradiated to the liquid membrane of the liquid metal ejected onto the back plate 906 and high-speed neutron is generated behind the target 901 by burnup.
In the structure of the liquid metal loop 900 of the related art, the liquid metal directly enters the liquid metal bulk from the tube inserted into the liquid metal of the quench tank 902, and hence the bubbles are mixed in the liquid metal. Since the diameter of the bubble is small and the rising speed thereof is slow, the bubbles circulate inside a loop while being contained in the liquid metal. Further, since an area where the liquid metal stays is needed so as to remove the bubbles, the device increases in size.